Sylvania



H. F. SHPHERD.

HOT PLATE APPARATUS.

Armenian min nov. 30. I911. RENEWED ms. 21. I919.

1 $317,899. Patented Oct. 7, 1919.

FIG-I I 6mm,

UNITED STATES PATENT OFFICE.

HAROLD F. SHEPHERD, OF GROVE CITY, PENNSYLVANIA, ASSIGNOR T0 BESSEMER GAS ENGINE COMPANY, OF GROVE CITY, SYLVANIA.

PENNSYLVANIA, A CORPORATION OF PENN- HOT-PLATE APPARATUS.

Specification of Letters Patent.

Application filed November 30, 1917, Serial No. 204,532. Renewed February 21, 1919. Serial No. 278,513.

paratus, of which the following is-a spec1-' fication.

This invention relates to hot plate apparatus and consists in certain improvements in the construction thereof as will be hereinafter fully described and pointed out in the claims.

More particularly the invention is designed as a starting plug for explosive engines of the hot bulb type but the invention in its broader phases is not so limited.

The invention is illustrated in the accompanying drawings as follows Figure 1 shows a central section of the end of an explosion chamber of an explosive engine equipped with the hot plate apparatus.

Fig. 2 shows an elevation of an alternative construction of a hot plate apparatus.

1 marks the cylinder, 2 the explosion chamber, 3 the hot bulb operating at the end of the explosion chamber, 3 a ring for securing the hot bulb in place and 4 a starting plug.

The starting plug comprises a hot plate in the form of a receptacle 5. The upper end of this receptacle is provided with a screw thread 6 which is inserted in a screwthreaded opening in the hot bulb. The receptacle contains a liquid 7 having a predetermined desired vaporizing point. This vaporizing point may be accomplished from the nature of the material used so as to have the desired pro-determined temperature at atmospheric pressure, or the pressure in the receptacle may be varied so as to vary the boiling or vaporizing point if desired. Ordinarilv mercury is used in the starting plug, this having a vaporizing point approximating that desired. If a slightly higher temperature is desired this mav be accomplished by subjecting the receptacle to a slight pressure and closing the receptacle by soldering. A water jacket 8 surrounds the outer end of the plug and is connected by the tubes 9 with the circulating system of the engine (not shown). This water jacket forms a condenser so that the vapor arising from the liquid when heated upon coming into contact with the upper walls of the receptacle adjacent to the Water jacket is immediately condensed and the liquid so condensed is returned to the body of the liquid 7. The condenser is practically insulated from the liquid in that the vapor in itself is not a good conductor of heat. The heat, however, is dissipated automatically through the partlcles of vapor acting on the condensing plates. At the same time the temperature of the plate from its direct contact with the liouid is maintained approximately constant at the vaporizing, point of the liquid.

In order to heat the plug when starting the engine an electric heating unit having a heatlng element 10 is used. This element is connected with the terminals 11 and 12 surrounded by an insulating coat 13 and a sheath 14. The heating unit, or element, is lmmersed in the liquid and heats the liquid to the vaporizing point and consequently heats the plate so as to start the engine.

The liquid not only maintains the plate below a temperature at which it can be injured through the excessive heat incident to the explosions of the engine but it also protects the plate against excessive heating through the action of the electric heating element 10.

The plug is preferably directly opposite the fuel injecting nozzle 15.

In Fig. 2 I have shown an alternative construction wherein an air cooling wall 8 is substituted for the water jacket 8. Otherwise the construction is similar to that shown in rig. 1.

What I claim as new is 1. A'hot plate apparatus comprising a receptacle. :1 wall of which forms the hot plate; a liquid in the receptacle in contact with the wall and vaporizing at a. predetermined desired temperature and dissipatin through vapor evolved any excess heat; an d electric heating element immersed in said liquid.

2. A hot pl ate appartaus comprising a fiuid receptacle; liquid in the receptacle vaporizing at a pre-determined desired temperature; an electric heating element immersed in said liquid; and means for condensing and returning the vapor.

3. A hot plate apparatus comprising a fluid receptacle, a wall of which forms the hot plate; a liquid in the receptacle in contact with said wall and vaporizing at atmospheric pressure at a redetermined desired temperature and dissipating through vapor "vol'ved any "excess heat and an electric heatmgeiement emer ed in said liquid.

4, A hot plate apparatus comprising a fluid receptacle, the wall of which forms a hot plate; li uid in said receptacle in contact with said van-vaporizing at a redetenafimd desired temperature and dissipating through Vapor evolved any excess heat; an electric heating element immersed in said liquid; and electric conductors for said element entering the receptacle above the liquid.

5. A hot plate apparatus comprising a plate support; a fluid receptacle, :1 wall of which below the support forms a hot plate, said receptacle extending above and below said support; a liquid in the receptacle in contact with said wall vaporizing at a desired predetermined temperature; a condenser above the support; and an electric heater immersed in the liquid.

6. Aliot plate ap aratus comprisingafluid receptacle the wall of which forms a hot plate receiving and discharging heat from Within and without; a liquid in said receptacle in contact with said wall; and an electric heating element immersed in said liquid, said liquid protecting said element from excess heat induced through the element itself or from without the wall of the receptacle.

In testimony whereof I have hereunto set my hand.

HAROLD F. SHEPHERD.

Copies of this patent may be obtained for fire-cents each, by addressing the "Commissioner of Patents, Washington, D. 0. 

